stream_restoration_session_for_wqgit_final

Report
Recommendations of the Expert Panel to
Define Removal Rates for Individual Stream
Restoration Projects
Presentation at Water Quality Goal
Implementation Team Meeting
May 13, 2013
Status of Expert Panel Report
• Expert Panel Reached
Consensus and Review
Period Completed
• Briefing of Federal
Stream Permitting
Agencies in March
• Response to 150 Pages of
Comments and Revised
Report Released in Feb
• Approval by WQTWG in
April and Final Version
Prepared
– (EPA, PADEP, VADCR,
WVDEP, Consultants, JHU,
MSRA…)
• Urban Stormwater
Technical Work Group
approval in Feb
• Agricultural Work Group
approval in May
• Seeking WQGIT approval
today
Expert Panel on Stream Restoration
Panelist
Affiliation
Deb Cappuccitti
Maryland Department of Environment
Bob Kerr
Kerr Environmental Services (VA)
Matthew Meyers, PE
Fairfax County (VA) Dept of Public Works and Environmental Services
Daniel E. Medina, PE
Atkins (MD)
Joe Berg
Biohabitats (MD)
Lisa Fraley-McNeal
Center for Watershed Protection (MD)
Steve Stewart
Baltimore County Dept of Env. Protection and Sustainability (MD)
Dave Goerman
Pennsylvania Department of Environmental Protection
Natalie Hartman
West Virginia Department of Environmental Protection
Josh Burch
District Department of Environment
Dr. Robert C. Walter
Franklin and Marshall College
Dr. Sujay Kaushal
University of Maryland
Dr. Solange Filoso
University of Maryland
Julie Winters
US Environmental Protection Agency CBPO
Bettina Sullivan
Virginia Department of Environmental Quality
Panel Support
Tom Schueler
Chesapeake Stormwater Network (facilitator)
Bill Stack
Center for Watershed Protection (co-facilitator)
Other Panel Support: Russ Dudley – Tetra Tech, Debra Hopkins – Fish and Wildlife Service,
Molly Harrington, CBP CRC, Norm Goulet, Chair Urban Stormwater Work Group, Gary Shenk, EPA
CBPO, Jeff Sweeney, EPA CBPO
Review of the Old Rate
Initial CBP-Approved Stream
Restoration Credit (2003)
Removal Rate per Linear Foot of Qualifying Stream Restoration
Source
Spring Branch
N=1
TN
TP
TSS
0.02 lbs
0.0035
2.55 lbs
At some point applied to non-urban stream restoration projects.
Approved Interim Rate
Edge-of-Stream 2011 Interim Approved Removal Rates per Linear Foot of
Qualifying Stream Restoration (lb/ft/yr)
Source
TN
TP
TSS*
New Interim CBP
Rate
0.20
0.068
310 (54.2)
Derived from six stream restoration monitoring studies: Spring Branch, Stony Run, Powder Mill Run,
Moore's Run, Beaver Run, and Beaver Dam Creek located in Maryland and Pennsylvania
*The removal rate for TSS is representative of edge-of-field rates and is subject to a sediment delivery
ratio in the CBWM to determine the edge-of-stream removal rate. Additional information about the
sediment delivery ratio is provided in Appendix B.
Why the initial credit needed to be changed
and a universal restoration credit doesn’t make
sense
Streambank Erosion Rate
(lb/ft/yr)
100,000
10,000
1,000
100
10
1
Edge-of-Field Erosion Rate (lb/ft/yr)
USGS Data Supports Stream Bank Erosion as a
Major Source to the Bay
Summary of Recommended Protocols
•
Protocol 1: Credit for Prevented Sediment during Storm Flow -- This protocol provides an
annual mass nutrient and sediment reduction credit for qualifying stream restoration
practices that prevent channel or bank erosion that would otherwise be delivered
downstream from an actively enlarging or incising urban stream.
•
Protocol 2: Credit for Instream and Riparian Nutrient Processing during Base Flow -- This
protocol provides an annual mass nitrogen reduction credit for qualifying projects that
include design features to promote denitrification during base flow within the stream
channel through hyporheic exchange within the riparian corridor.
•
Protocol 3: Credit for Floodplain Reconnection Volume-- This protocol provides an annual
mass sediment and nutrient reduction credit for qualifying projects that reconnect stream
channels to their floodplain over a wide range of storm events.
•
Protocol 4: Credit for Dry Channel Regenerative Stormwater Conveyance (RSC) as an Upland
Stormwater Retrofit-- This protocol provides an annual nutrient and sediment reduction rate
for the contributing drainage area to a qualifying dry channel RSC project. The rate is
determined by the degree of stormwater treatment provided in the upland area using the
retrofit rate adjustor curves developed by the Stormwater Retrofit Expert Panel.
Stream Restoration Protocols
1. Prevented sediment approach
3. Flood plain reconnection
2. In-stream denitrification
4. The “tweener” Dry Channel RSC
Protocol 1: Credit for Prevented Sediment
during Storm Flow
This protocol provides an annual mass nutrient and
sediment reduction credit for qualifying stream
restoration practices that prevent channel or bank
erosion that would otherwise be delivered downstream
from an actively enlarging or incising urban stream.
• Estimate stream sediment erosion rates
• Convert erosion rates to nitrogen and phosphorus loadings
• Estimate reduction efficiency attributed to restoration
Protocol 1: Credit for Prevented Sediment
during Storm Flow
Step1.Estimate Stream Sediment Erosion Rates Using the
BANCS Method
Streambank
Characteristics
used to develop
BEHI
Velocity
Gradient and
Near-Bank
Stress Indices
Protocol 1: Credit for Prevented Sediment
during Storm Flow
Regional Curve for Determining “R” in equation: S = ∑(C×A×R)
Curve for Hickey Run –
Washington DC- USFWS
Protocol 1: Credit for Prevented Sediment
during Storm Flow
Step 2.Convert erosion rates to loadings
S=∑(c x A x R ) / 2,000
• Where: S = sediment load (ton/year) for reach or
stream
• c = bulk density of soil (lbs/cubic foot)
• R = bank erosion rate (feet/year) (from regional
curve)
• A = eroding bank area (square feet)
• 2,000 = conversion from lbs to tons
Multiply sediment load times TN and TP
concentrations
Table 5: TN and TP Concentrations in Sediments in Different Parts of the Urban Landscape1
Location
Upland Soils
Median
TP
0.045
Street Solids
0.52
TP Range
0.00250.577
0.19-0.72
Catch Basin3
0.49
0.057-0.97
1.74
0.055-6.27
MD
Law et al. 2008
BMP
Sediments
Streambank
Sediments
0.29
0.014-1.38
1.47
0.11-5.6
National
Schueler, 1994
0.439
0.19-0.90
--
--
MD
BDPW, 2006
0.445
0.072-4.43
1.35
0.0015-4.13
MD
Stewart, 2008
1.61
0.357
0.23-4.69
3.81
1.1
0.7-1.7
MD
PA
Stewart, 2012
Land Studies, 20052
1.05
--
2.28
--
PA
Walters et al, 20072
1 all
Median
TN
0.8
TN Range
0.05-3.3
Location
MD
1.08
0.324-2.71
MD
Diblasi, 2008
units are lb/ton
the Pennsylvania data on stream bank sediments were in rural/agricultural subwatersheds
3 catch basin values are for sediment only, excluding leaves
2
Reference
Pouyat et al. 2007
Protocol 2: Credit for Denitrification in the
Hyporheic Zone during Base Flow
(for projects that qualify for Protocol 1 but not Protocol 3)
Step 1.Determine the total post construction stream length that has been
reconnected using the bank height ratio of 1.0 or less (for NCD) or the 1.0
inch storm (other design approaches that do not use the bank full storm)
Step 2. Determine the dimensions of the hyporheic box
Step 3. Multiply the hyporheic box mass by the unit denitrification rate
5 feet + stream width + 5 feet
5 feet depth
Protocol 3: Credit for Floodplain Reconnection
(for
projects that qualify for Protocol 1 but not Protocol 2)
Annual mass nutrient reduction credit for projects that
reconnect stream channels to their floodplain over a wide
range of storm events
Protocol 3: Credit for Floodplain
Reconnection Volumes during Storm Flow
Step 1.Estimate the floodplain connection volume
Annual runoff volume going to
floodplain wetlands when floodplain
is accessed at 1.0”
Annual runoff volume going to
floodplain wetlands when floodplain is
accessed at 0.5”
In-channel flow
Protocol 3: Credit for Floodplain Reconnection
Volumes
Step 2.Estimate the N and P removal rate attributable to
floodplain reconnection (using Jordan 2009 study)
Protocol 4: Dry Channel RSC as a
Stormwater Retrofit
The Panel decided to classify dry channel RSC systems as an upland
stormwater retrofit. Designers should use the protocols developed by the
Urban Stormwater Retrofit Expert Panel to derive the sediment and
nutrient removal rates.
The general process is to determine runoff reduction credit from adjustor
curves that determine TP, TN, and TSS removal rates based on the depth
of rainfall captured over the contributing impervious area treated by the
RSC.
The final removal rate is then applied to the entire drainage area to the
dry channel RSC project.
Protocol 4: Dry Channel RSC as a
Stormwater Retrofit
Upland Restoration vs. Stream Restoration
Comprehensive Watershed Restoration
Approach
• Panel endorsed a
comprehensive watershed
approach to install
restoration practices in
the uplands, the stream
corridor, and in
appropriate settings,
within the stream itself
• No current science to
recommend what
proportion of practices
should be applied to
uplands vs. stream corridor
Qualifying Conditions
 Stream restoration projects that are primarily designed to protect public
infrastructure by bank armoring or rip rap do not qualify for a credit.
 The urban stream reach must be greater than 100 feet in length
 The project must utilize a comprehensive approach to stream restoration
design, involving the channel and banks.
 Stream restoration project MUST provide a NET watershed removal
benefit in order to be eligible for either a sediment or nutrient credit.
 NO removal credit will be granted for any project that is built to offset,
compensate, or otherwise mitigate for an impact to a stream or waterway
elsewhere in the watershed
Environmental Concerns
 Each project must comply with all state and federal permitting
requirements, including 404 and 401 permits, which may contain
conditions for pre-project assessment and data collection, as well as
post construction monitoring.
 Stream restoration is a carefully designed intervention to improve the
hydrologic, hydraulic, geomorphic, water quality, and biological condition
of degraded urban streams, and cannot and should not be implemented
for the sole purpose of nutrient or sediment reduction.
 There may be a few classes of legacy sediment stream restoration
projects that do not fall into the preceding statement. Also, there may
instances where limited bank stabilization is needed to protect critical
public infrastructure (which may need to be mitigated and does not
qualify for any sediment or reduction credits).
Environmental Concerns
 A qualifying project must meet certain presumptive criteria to ensure that highfunctioning portions of the urban stream corridor are not used for in-stream
stormwater treatment (i.e., where existing stream quality is still good). These may
include one or more of the following:




Geomorphic evidence of active stream degradation (i.e., BEHI score)
An IBI of fair or worse
Hydrologic evidence of floodplain disconnection
Evidence of significant depth of legacy sediment in the project reach
 Stream restoration should be directed to areas of more severe stream impairment,
and the use and design of a proposed project should also consider the level of
degradation, the restoration needs of the stream, and the potential functional uplift.
 Before credits are granted, stream restoration projects will need to meet postconstruction monitoring requirements, document successful vegetative establishment,
and conduct initial project maintenance.
 A qualifying project must demonstrate that it will maintain or expand riparian
vegetation in the stream corridor, and compensate for any project-related tree losses
in project work areas.
 All qualifying projects must have a designated authority responsible for development
of a project maintenance program that includes routine and long-term maintenance.
Functional Uplift in Streams
5 minutes
The “Test-Drive” Process
 Recommended protocols are new, somewhat complex and
will require project-based interpretation on the part of
practitioners and regulators alike.
 Panel strongly recommends that both groups should "testdrive" the protocols on real world projects over the next
six months.
 Based on their collective experience, convene a Bay-wide
meeting to develop any additional supplemental information
or procedures to effectively implement the protocols.
 Series of webcast or workshops to deliver a clear and
consistent message to the Bay stream restoration
community on how to apply the protocols.
Initial Verification of Performance
 Prior to submitting the load reduction to the state
tracking database, the installing agency will need to
provide a post-construction certification that the
stream restoration project:
was installed properly,
meets or exceeds its functional restoration objectives
hydraulically and vegetatively stable,
 Initial verification is provided either by the
designer, local inspector or state permit authority
Verification of Stream Restoration Credit
• Max duration for the removal credits is 5 years
• Credit is renewed based on a field performance
inspection that verifies the project still exists,
is adequately maintained and operating as
designed.
• Credit is lost if project cannot be verified (i.e.,
does not pass inspection).
• This creates strong incentive for localities to
monitor the long term performance of their
projects
Reporting Requirements
Historic
Project
Use
interim
efficiency
removal
rate
Stream Project
Non-Conforming
Project
Conforming
Project
Use new
Protocols
Reporting Needs:
Type
Use
Length
Interim
Protocol(s) Used
removal
12 Digit Watershed
rate
Date Installed
Location, DA and land
Reporting
cover treated
Needs:
Projected TSS, TP
Length
and TN Load
Date
Reduction
Installed
Wetland area and FP
Location
connection storm
More detailed project data and protocol computations to be
Hyporheic box
archived in permit files, a subset of which may be audited or dimensions and BH
ratio
cross-checked by state agencies
Questions?

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